Plants require several essential elements for growth. These elements are not always found in the proper amounts in the soil giving a marked decline in crop productivity. By the mid 20th century the agricultural land in most of the world had in a sense been mined of its fertility. Crops were harvested taking the essential elements out of the soil with none being returned.
Various types of material now called "commercial fertilizers" soon became available in an attempt to increase productivity. Liquid, gaseous and solid fertilizers are available each claiming advantages. The application of the fertilizer can take place at various stages such as treating the seed before planting, ground treatment before planting, while planting, post emergent and on the foliage.
As the various types of fertilizers developed so did the machines with which to apply them. Placing seaweed, manure, or other solid chemicals on the soil and cultivating it in gave way to placing the fertilizer where it would do the most good at the least cost. With the increased environmental awareness, spiraling energy costs and more emphasis on retaining crop residue on the soil surface to prevent erosion, applicants practical and efficient fertilizer apparatus could not be more timely. Various machines now in use place the fertilizer beneath soil close to the roots which is most desirable. However, many of these machines cannot apply the fertilizer at various stages of plant growth or to various types of soil applications. Plant damage, mechanical failure and plugging up of flow during ground penetration are all attendant problems of the majority of machines now in use.
A search of the prior art has revealed several U.S. Pat. Nos., those deemed most relevant being 4,649,836, 4,178,860, 2,876,718 and 2,649,060. U.S. Pat. No. "836" discloses a device for injecting liquid fertilizer into the soil by radial spoke injectors on a rotating hub but for distribution to the spokes uses a central disk formed with a socket adapted to hold a metering bushing slidable axially in the socket directing the fluid from the disk to a desired spoke. In contrast applicants device has a circumferentially compressible split sleeve for sealed distribution to a spoke having a specific ground engaging end and orifice. U.S. Pat. No. "860" also has tines or spokes which penetrate the ground surface to carry a liquid fertilizer controlled by a rotary distribution valve directly connected to a chain drive while applicants device has a stationary circumferentially compressible split sleeve distribution valve distributing liquid fertilizer to a spoke having a specific ground engaging end and orifice. U.S. Pat. No. "718" teaches both an axle bore and hub bore precision fit and lining up for fluid conduction and a spring loaded disk and axle with bore lining up with a hub bore for the fluid conduction. These however bear no resemblance to applicants split sleeve expansion fit valving arrangement nor is there taught applicants specific ground engaging tip. U.S. Pat. No. "060" teaches a main shaft bored to receive fluid, then conduit-transferred to another shaft by means of a cam actuated valving arrangement, to the ground engaging injection tubes. The injection tube nozzles are tapered to one side for ease of ground penetration. Applicants device in contrast as heretofore mentioned has a very simple single split sleeve distributor valve and a protected countersunk orifice for fluid transfer to the soil. It is abundantly clear from the above that applicants device avoids all known prior art since there cannot be found in a single reference or combination of references any suggestion that could be construed as pointing towards the herein disclosed instant invention.